The routing of a toll free (“TF”) telephony call in North America is determined by a single toll free number (“TFN”) database (“SMS/800 Database”). A telephony call is sometimes referred to herein as a “call” or “telephony call.” The SMS/800 Database is administrated under authority of the Federal Communications by Somos Inc. (“Somos”), formerly known as SMS/800, Inc. The SMS/800 Database is updated by responsible organizations (“Responsible Organizations” or “RespOrgs”) who operate in accordance of SMS/800 Database guidelines promulgated by Somos. The RespOrgs are responsible for administering TFNs acquired by them from Somos or transferred to them from other RespOrgs. For each such TFN the RespOrg is charged with updating the SMS/800 database, as applicable. Important fields in the SMS/800 Database include the TFN, RespOrg identifier (“RespOrg ID”) associated with the TFN, and a carrier identification code (“CIC”) that identifies a carrier to which an access tandem will often route the TF telephony call over a network for an inter-LATA telephony call. The TFN record information input by the RespOrg into the SMS800 Database is downloaded to appropriate service control points (“SCPs”) based on the area of service indicated in the TFN record.
In the legacy time division multiplex (“TDM”) telephone network, a TF call travels from the caller's equipment via an Incumbent Local Exchange Carrier (“ILEC”) switch at a Central Office (“CO”) local to where the TF call originated. Either the CO switch, or an access tandem connected to the CO switch, “dips” the SMS/800 Database at a SCP to retrieve a CIC associated with the dialed TFN. Based on the CIC, the ILEC routes the TF call via a TDM access tandem to an interexchange carrier (‘IXC″) associated with the CIC. The IXC transports the call over its network to the local exchange where the toll free call is completed.
Originally AT&T provided the tandem facilities, called tandems, to which carriers connected at a meet-me point. The AT&T tandem received a TF call, and based on the CIC associated with the TF call, delivered the call to the carrier associated with the CIC. Subsequent to the breakup of the Bell System in 1982, some of the spun off independent Regional Bell Operating companies (′RBOC″) grew in part by acquiring, being acquired or merging with other telephone companies. As of today there are only a few primary carriers that own tandem facilities used for routing and transporting TF calls (“Primary Tandem Access Switch Providers”). The Primary Tandem Access Switch Providers include AT&T (name now used by SBC Communications, who acquired AT&T Corporation, Ameritech, Pacific Telesis, SNET and BellSouth), Verizon Communications (“Verizon”) (resulting from a merger of Bell Atlantic, NYNEX and GTE), and CenturyLink (who acquired Qwest Corporation, formerly known as Mountain Bell).
Other carriers depend on the Primary Tandem Access Switch Providers for routing and transport of TF calls. In the event of a failure of one or more Primary Tandem Access Service Providers, long distance TF calls routed to such provider(s) will not complete. One recovery option is a manual update of the SMS/800 Database, whereby the RespOrg having responsibility for the affected TFN changes the CIC associated with such TFN to a CIC of an alternate Primary Tandem Access Switch Provider not experiencing a failure. In the case of a catastrophic failure of one or more Primary Tandem Access Switch Providers, potentially millions of TF telephony calls will fail to complete. Updates of the SMS/800 Database after a toll free call fails to complete is not a time-efficient solution, particularly from the perspective of the caller.
An Internet (“VoIP”) service provider (“VoIP Service Provider”), sometimes referred to herein as a telephony service provider or a service provider, may not have an ability to originate or terminate a TF call directly to TDM tandems. Such VoIP Service Provider may be dependent, at least in certain instances, on accessing the SMS/800 Database via a SCP to obtain a CIC associated with the TFN. The VoIP Service Provider routes the TF call via an access tandem to the IXC associated with the retrieved CIC. A failure of the Primary Tandem Access Switch Provider to complete a TF call can cause the same problem for a VoIP Service Provider as for other carriers.
Conventional architectures for routing TF telephony calls do not incorporate the ability to efficiently re-route a TF telephony call in the event of failure of the TF call to complete due to a failure at a Primary Tandem Access Switch Provider.